These are three Transistor tester circuits into the Circuit or PCB. When your project do not works, the tester electronic parts or component be what need very much. Only by measuring transistor I’m tired of having to remove out one by one measuring. It wastes time and makes damage to the PCB. This circuit help make life easier. Easy to use because you do not need remove the transistor form PCB still check it. Making we save time a lot.

I recommend all 3 circuits as follows.

1.in circuit transistor tester schematic

You just know only Position legs of transistor. then place the probe and press s1 , see the led indicator good or bad of the transistor easily. It use the nand gate digital CMOS IC-4011 series or CD4011 or MC14011 or TC4011 so useful IC very low cost. The power Supply we use battery 9volt for this circuit has low current when measure in circuit.
As show circuit figure above.

How to makes it.
This circuit is very easy to use, so we use the peforated board, reducing the time to make this project a lot. However you should check out the the circuit carefully. To ensure the accuracy.

This circuit works you can watch video below.

Thanks

2. Fast transistor tester circuits

This circuit design, to determine quickly the transistors only. when not have time,or need to check the a lot equipment. This circuit have a simple way to work,In the test battery position (turn off switch S2).Moving coil meter 10 mA, in series with a resistance of 600 ohms(R4+R5) .When connected to a battery, 6V, so the current 10mA(moving coil current). flow meter with a needle full scale, it is available.

When the transistor was tested.(S2 open, S3 is in position 2 or 3) The current will flow through the join junction base – emitter of the transistors were tested. This value can be calculated.By dividing the voltage drop across R1 or R2, with its resistance. When S3 is in position 2 is (6V-0.6V / 560K = approximately 10 micro-amps). That is why the needle meter indicates full scale. Which indicates that the transistor is also available.

When S2 is in position 2 will be multiplied by a factor of 100. The rate of increase (hfe) of the transistor.In position 3, the resistor at base pin will be lower than the 10 times (R1 = 56K). Therefore, the value must be multiplied by 10. For switch S1 to switch the transistor is NPN or PNP.

3. Checking Transistor with the sound

This circuit uses to check transistor get accurately and fast. By the way will check to tell with sound signal which , pertaining to the expansion ratio of transistor. Then help reduce the expenses in tool expensive buying. The transformer T1 in a picture is model output transformer at use prevent general in the receiver transistor the general. With regard to have consuming trend low make use battery 9V get long moderately ago. The royal utensils is model use 8ohm loudspeakers. And usability have S1 do infront on-off and choose a kind NPN and PNP of transistor for S2 use press when want to check each time. Friends can see the detail adds in the circuit yes.

Relate circuits link (sometime you may use it)